1. Field of the Invention
The present invention relates to a fuel tank.
2. Description of Related Art
As a fuel tank provided in an automobile, there is such a structure in which a reinforcement device is provided between a top face and a bottom face of a tank so as to absorb both a compression force and a tensile force, as described in Japanese Patent Application Publication No. 2012-35914 (JP 2012-35914 A).
However, the structure described in JP 2012-35914 A is configured such that wall portions are prevented from moving away from each other by axially fastening means when a pressure in a fuel tank 1 is increased. This results in that the structure cannot tolerate deformation (volume change) of the fuel tank. Further, when an internal pressure of the fuel tank is decreased, a spring device is compressed, so that it is difficult to keep a given deformation amount of the fuel tank.